The recovery of gold cyanide from a cyanide leach pulp (C.I.P. Process) by contact thereof with activated carbon has become an extremely successful method of recovery of dissolved gold resulting in high recoveries and, correspondingly, low losses in the tailings.
The commonly used C.I.P process involves the use of a series of tanks or pachucas in which the pulp and carbon are contacted countercurrently. This is generally achieved by having a steady flow of pulp through the series of adsorption vessels coupled with the periodic transfer of carbon, usually with its associated pulp, in a countercurrent direction. This arrangement involves the use of screens through which the pulp must flow in order to maintain the carbon in a particular vessel and these retaining screens do create appreciable problems.
Also, mechanical agitators are normally employed and these tend to abrade the carbon to some extent.
Furthermore the transfer of carbon in the countercurrent direction is generally achieved using either submersible pumps or airlifts, which constitute additional equipment with attendant capital costs and additional abrasion of the carbon granules.
The total residence time of the pulp in such a C.I.P gold recovery plant is generally of the order of about six hours and, accordingly, the size of the vessels has to be appreciable in order to provide for such an overall residence time.
It is the object of this invention to provide a process for the recovery of gold from leach pulp by the direct contacting thereof with activated carbon but wherein many disadvantages associated with the prior art stirred vessel arrangement are obviated and a plant of a smaller size can be used for the same throughput.